根据句意及首字母提示补全单词或词组。
①He wants to ____ (训练)his worker for the work.
②I am not sure.____ (也许)you are right.
③.Smoking is bad for our ____(健康).
④Many of us have ____ (听说)the film Walking with Dinosaurs (《与恐龙同行》) ,but no one has seen it.
⑤His parents want him to____ (退学)and help them work on the farm.
